This page is a Javascript version of the 1915 Negretti and Zambra (Zambretti) weather forecaster which was originally designed for the Northern Hemisphere and UK 'Weather Range'. The algorithm has been re-written to allow for any location worldwide and the choice of 'Wind Direction' has been increased to 16 points to give greater precision.

A forecast made at approximately 09:00 local time is reportedly better than 90% accurate, even though it takes no account of rate of barometer change, wind speed or temperature!